of calcium. If a person consumes 0.06 g of calcium‚ how many moles of calcium did he consume? 1.5x10-3 mol What is the empirical formula of a compound that contains 20% calcium and 80% bromine by mass? CaBR2 Calculate the number of hydroxide ions present in 0.250 mol of Ca(OH)2. 3.01x1023 |What is the volume occupied by 0.25 moles of Nitrogen at STP? | | | 5
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Describe the difference between a mixture and a compound. A compound is a substance in which atoms of different elements are chemically held to one another. A mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. A mixture can usually be separated back into its original components‚ a compound cannot. Below are some examples of the differences between each. Compounds •Compounds are pure substances. •They are made up of two or more
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When you mix copper‚ silver‚ and nitrate together‚ you will end up with silver nitrate solution will turn blue (it has become copper nitrate). On the piece of copper‚ there would be a coating of solid silver. If a chemical reaction is going to be observed when chemicals are mixed‚ heated or any other means of altering the substance‚ then we will be able to predict the products formed. If it is observed that in the original versus the changed substance no new substances are formed‚ the change is reversible
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Name: __________________________________ Teacher: ________________________________ DO NOT OPEN THE EXAMINATION PAPER UNTIL YOU ARE TOLD BY THE SUPERVISOR TO BEGIN Chemistry 2202 FINAL EXAMINATION June 2010 Value: 100% General Instructions This examination consists of two parts. Both parts are contained in this booklet and further general instructions are provided on appropriate pages. Part I – Multiple Choice (40%) Select the letter of the correct response from those provided. EITHER
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three examples of percent compositions determined to help narrow the selection of possible unknowns. Titrations using Na2S2O3 and HCl to determine percent cobalt and ammonia‚ respectively‚ are used. Silver nitrate is used to precipitate the chloride ions in the unknown‚ which can be measured to determine the percent composition of chloride in the unknown. The results from these three major analyses helped to draw the conclusion that the unknown is in fact [Co(NH3)6]Cl3. -2.0 Synthesis/Analysis of
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“WATER IS A GOOD SOLVENT” Water is very unique in all facets of its nature. The chemical formula for water is H2O as a water molecule consists of two atoms of the chemical element hydrogen (H) and one atom of the element oxygen (O). Water is the most abundant chemical compound on earth as its mass all exists together‚ naturally‚ in its gaseous‚ liquid and solid state. It is the most precious natural resource to man and is essential to life for all discovered living organisms. One of the unusual
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4. List the three fluid compartments and the percentage of total body water in each. a. Intracellular 62% b. Interstitial 30% c Plasma 8% 5. Give an example of each of the following solutes: a. Ions/electrolyte: Sodium ion b. Colloids: Proteins c. Nonelectrolytes: Glucose 6. List the major extracellular and intracellular cations and anions a. Extracellular cations: Sodium anions: Chloride b. Intracellular cations:
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the protons are not equal to the electrons ion the protons are not equal to the neutrons isotope atomic mass = mass of protons + neutrons changing the number of neutrons does not influece the mass or electrons atom behaviour is because of electrons hydrogen almost always loses its electron‚ leaving it a hydrogen ion taking away a negative charge creates a cation adding a negative charge creates an anion electronegativity is the ability to steal electrons electronegativity is influenced
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ppt. [h] Insoluble in excess aq. NaOH. Fe2+ + 2OH- Fe(OH)2 (dark green ppt) Reddish-Brown ppt. [k] Insoluble in excess aq. NaOH. Fe3+ + 3OH- Fe(OH)3 (red brown ppt) iron (II) iron(III) NOTE: The observations for both lead(II) and aluminium ions are similar. To distinguish them‚ add aqueous potassium iodide KI to both solutions.
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Pre-Lab Work Sheet Which type of compound usually has higher melting points: ionic compounds or covalent compounds? What is the reason for this difference in melting points? (3 points) Ionic compounds have higher melting and boiling points than covalent compounds. The electrostatic attraction in an ionic bond is very strong hence a lot of heat energy is required to break it down‚ ionic bonds have high melting and boiling points. In covalent bonds‚ the intermolecular forces are very weak and
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